Refer to Problem Show that the exact annual compound rate of growth of an investment that doubles in n years is given by r= 100 (21/n - 1). Graph this equation and the rule of 72 on a graphing calculator for 5 s n s 20.
Ina conversation with a friend, you note that you have two real estate investments, one that has doubled in value in the past 9 years and another that has doubled in value in the past 12 years. Your friend says that the first investment has been growing at approximately 8% compounded annually and the second at 6% compounded annually. How did your friend make these estimates? The rule of 72 states that the annual compound rate of growth rof an investment that doubles in n years can be approximated by r 72/n Construct a table comparing the exact rate of growth and the approximate rate provided by the rule of 72 for doubling times of n = 6, 7, ..., 12 years. Round both rates to one decimal place